The difficulty of rebuilding Notre Dame-an expert weighs in

Interview with Manfred Curbach, a professor and one of the engineers behind the reconstruction of Dresden’s Frauenkirche church.

SPIEGEL ONLINE:Mr. Curbach, how do you rebuild a church like Notre Dame, which is more than 800 years old?

ManfredCurbach:That depends greatly on how severe the damage to the walls is. The Frauenkirche in Dresden was also destroyed by fire during World War II, with the church’s interior burning for 26 hours. The natural stones from which the Frauenkirche and most of Notre Dame are built stand up well to fire. The problem lies in the heat generated by the fire.

SPIEGEL ONLINE:What about NotreDame?

Curbach: The big question is how hot the stone became. If just a bit of material broke off, then it can be repaired quite easily. Individual stones can also be replaced if they are damaged. But first they have to examine how stable the structure now is in its entirety.

SPIEGEL ONLINE:You saw the photos. How great do you think the chances are that the fire destabilized the entire cathedral?

SPIEGEL ONLINE:How can the roof be rebuilt?

Curbach:It’s important to have good plans. There’s a 3D model of Notre Dame, which will make reconstruction considerably easier, because you know exactly how the beams were arranged before the fire. But it will nonetheless be a great challenge, because Gothic buildings are very delicate and have many fine elements.

SPIEGEL ONLINE:And the roof itself?

Curbach:It’s difficult to say whether lead will be used here again. It will come down to whether monument conservationists prevail and insist that everything be restored absolutely true to the original, or whether deviations are acceptable. If modern materials are accepted, it would also be possible to install modern insulation with foils and mats.

SPIEGEL ONLINE:How long do you think the rebuilding process will take?

Curbach: There is a lot of logistics and planning involved in a project like this. The roof truss was a work of art. Reconstruction will take years, perhaps even more than a decade.